How did ultra-processed foods take over, and what are they doing to us?

Sliced supermarket bread, ham, cheese, crisps, a fruit-flavoured yoghurt and a fizzy drink. If this sounds like a standard lunch, you're not alone. The average person in the UK gets more than 50% of their calories from ultra-processed foods - otherwise known as industrially produced edible substances'. Madeleine Finlay speaks to Dr Chris van Tulleken about what ultra-processed foods are really made of, how they have become a major part of our diets, and the impact they are having on our health